Influence Rules Research Articles

Electro-mechanical coupling band gaps of a piezoelectric phononic crystal Timoshenko nanobeam with surface effects

Plane wave expansion (PWE) method is extended to calculate the band structures of a proposed piezoelectric phononic crystal (PC) nanobeam by applying surface elasticity and Timoshenko beam theories. The calculation method is derived and formulized in detail. Further, electrical voltage and external axial force are picked to study the effects of electro-mechanical coupling fields on band gaps, residual surface stress and material intrinsic length are chosen to research the influences of surface effects on band gaps, and ratio between lengths of PZT-4 and epoxy in a unit cell and height-width ratio are picked to investigate the effects of geometric parameters on band gaps. In addition, all the results are compared to those in Euler nanobeam with same parameters. All the results and further analysis demonstrate that the influence rules will play an active role in design process and active control of nano electro-mechanical system based on piezoelectric PC nanobeam.

Use of a controlled experiment and computational models to measure the impact of sequential peer exposures on decision making.

It is widely believed that one's peers influence product adoption behaviors. This relationship has been linked to the number of signals a decision-maker receives in a social network. But it is unclear if these same principles hold when the "pattern" by which it receives these signals vary and when peer influence is directed towards choices which are not optimal. To investigate that, we manipulate social signal exposure in an online controlled experiment using a game with human participants. Each participant in the game decides among choices with differing utilities. We observe the following: (1) even in the presence of monetary risks and previously acquired knowledge of the choices, decision-makers tend to deviate from the obvious optimal decision when their peers make a similar decision which we call the influence decision, (2) when the quantity of social signals vary over time, the forwarding probability of the influence decision and therefore being responsive to social influence does not necessarily correlate proportionally to the absolute quantity of signals. To better understand how these rules of peer influence could be used in modeling applications of real world diffusion and in networked environments, we use our behavioral findings to simulate spreading dynamics in real world case studies. We specifically try to see how cumulative influence plays out in the presence of user uncertainty and measure its outcome on rumor diffusion, which we model as an example of sub-optimal choice diffusion. Together, our simulation results indicate that sequential peer effects from the influence decision overcomes individual uncertainty to guide faster rumor diffusion over time. However, when the rate of diffusion is slow in the beginning, user uncertainty can have a substantial role compared to peer influence in deciding the adoption trajectory of a piece of questionable information.

Mathematical Model for Analyzing Heat Transfer Characteristics of Ablative Thermal Insulating Material

A mathematical model based on minimal thermal resistance and equal law of specific equivalent thermal conductivity is developed to discuss the heat transfer characteristics of ablative thermal insulating material from the mesoscopic scale. Based on the statistical results of mesoscopic parameters, the microstructure unit cell model was established to analyze the influence rule of mesoscopic parameterization which includes the size, distribution, and positional relation of microsphere and fiber. The results show that the equivalent thermal conductivity decreases with the density, size, distribution area, and distance of microsphere and the space distance and volume fraction of fiber decreasing. Besides, the equivalent thermal conductivity will become larger when more quality of heat transfers along the fiber direction. Exploring the relationship between the macroscopic heat transfer process and the microstructure is meaningful for exploring the heat transfer behavior of thermal insulating material and improvement of the processing technology.

Modeling and analysis method of fractional‐order buck–boost converter

SummaryIn this paper, the equivalent small parameter method (ESPM) is used to establish the nonlinear mathematical model of the fractional‐order buck–boost converter in continuous current mode (CCM), and the analytical expression of approximate steady‐state period of converter state variable is obtained by using equivalent small parameter method and combining with harmonic balance principle. The Matlab/Simulink is used to construct the fractional‐order capacitance and inductance and to build the circuit model as well as the simulation model of fractional‐order buck–boost converter. Moreover, the simulation results of Oustaloup circuit model and numerical simulation model are compared with those of ESPM model to verify the validity and accuracy of the ESPM. The model is simulated by changing the orders of the capacitor and inductor to obtain the influence rule of the order of fractional element on harmonic characteristics of the state variables.

RETRACTED ARTICLE: Association rule generation and classification with fuzzy influence rule based on information mass value

The association rule based classification is imperative in the disease prediction owing to its high predictability. To deal with the sensitive data, we propose an algorithm using fuzzy inference set. The association rule mining is improved further by generating an associative rules for each item of the data set. The ranking of the item in the data set is based on the information mass value estimated. The mass value represents the depth of the item in the data set and its class. Selection of the certain item set is done based on the mass value of different associated items. According to the associative items selected, the association rule mining is performed. For each association rule generated, this method calculates the impact of each object from the rules based on how fuzzy rules are generated. Fuzzy impact rules indicate symptoms and diagnostic labels. A class of disease posses disease influence measure that predicts each class of disease has changed. The proposed algorithm improves the classification efficiency and reduces the error rates.

In-situ experiment investigations of hydrothermal process of highway in deep seasonal frozen soil regions of Inner Mongolia, China

To reveal the influencing factors and changing rules for the hydrothermal interaction process of highway subgrade, the field measurements of Shiwei-Labudalin Highway in Inner Mongolia, China was conducted for 3 years, based on which the freezing-thawing rules and water content changing characteristics were analyzed. The main results show the subgrade presents a frequent freezing-thawing alternation, and the water content of subgrade exhibits an obvious seasonal alternation. The subbase has the maximum water content, while the base has the minimum water content. The change of water flux is concentrated in the thawing period and consistent with the change of temperature gradient. The subbase layer has the most active water flux due to the heat absorption and impermeability of pavement that easily causes the water accumulation in this layer. Therefore, the prevention and treatment for the freezing-thawing disease should be started from heat insulation and water resistance.

Study on Mechanical Properties of Weakened Steel Frame Joints at Beam Ends

In order to study the hysteretic properties of steel frame T-shaped weakened joints, 12 groups of steel frame weakened joints and 1 group of common joints are designed with the weakened form, the weakened diameter and the distance from the weakened center to the column end as the parameters. Based on simplified mechanical model and material constitutive relationship, the finite element model is established by ABAQUS software to analyze the hysteretic properties of the joint specimen. By comparing with the existing test results of the weakened joint, both have a good agreement, and the rationality of the finite element model is verified. The simulation analysis of the weakened joints of the beam webs is carried out in the further and the load-displacement hysteretic curves are extracted as well as skeleton curves and stress cloud diagram of the joints. The influence rules of the weakened form, weakened diameter and weakened distance from the center to the column end on the seismic performance of the joints are obtained, and the design suggestions for the weakened joints are put forward. These can lay a foundation for time-history analysis of the frame structure with this kind of joints.

Influence of electric field on the ice‐coating process of insulators with a different dielectric surface

Studying the influence of electric field on the icing process of insulators with various dielectric surfaces is of great importance to the design of external insulation. This study established a finite element model to simulate the distribution of electric field around various insulator strings. Energised and non-energised icing tests were conducted to obtain the influence rules of electric field on the insulator icing process. The results of water droplets freeze experiment provided microscopic explanation of icing tests. Research results indicate that electric field and surface dielectrics have influence on the appearance, density and mass of ice on insulators. In microcosmic view, water droplets on super-hydrophobic surface correspond to longer freezing time and smaller average diameters, which leads to the better anti-icing character of super-hydrophobic insulator. Different types of ice branches appear in the water droplets freezing process on various dielectric surfaces. Owing to the polarisation effect, electric field can inhibit the formation and growth of ice branch, which contributes to different anti-icing characters of various dielectric surfaces in electric field. The effect of dielectric surface on insulator icing process mainly act at the initial period, surface coatings of insulators are not suggested to be applied in heavily icing area.

Research of Contact Response of an Elastic Sphere Impacting a Rigid Plate Based on the Mass-Spring-Damped Oscillator Model and Dimensionless Parameter \omega_\Omega

The contact theory, such as the Hertz theory and Hunt-Crossley model can just solve the contact response when the sphere goes to the maximum compression but can't solve the contact process. In traditional research the impact process is considered as a single degree of freedom dynamical spring-damping system, however, the calculated contact force is much greater than the actual one. Based on the shortage of the conducted studies, a new dimensionless parameter Omega is proposed in this paper, the mass-spring-damped oscillator model (MSDOM) and the new contact theory with the consideration of the sphere mass and Omega are established. The correctness of the theoretical model is verified by 3D simulation, and the optimal contact force model is obtained. Furthermore, influence rules of material properties and contact parameters on contact response were studied. The results show that the contact deformation, velocity, piecewise nonlinear contact force and acceleration based on MSDOM and Omega are effective to calculate the contact response. The contact stiffness, damping, material properties of sphere and elastic modulus of the plate have different influence on the contact response while the Poisson's ratio nu_2 has little effect on it.

Performance Evaluation of Degradable Temporary Plugging Agent in Laboratory Experiment

Abstract Temporary plugging fracturing is an effective way to enhance the fracture complexity and increase the stimulated reservoir volume (SRV) of unconventional reservoirs. The performance of temporary plugging agents (TPA) directly affects the success rate of temporary plugging. Currently, laboratory evaluation of the plugging effects of the TPA is rarely reported, and there are no industrial standards on laboratory evaluation of TPA plugging. In this study, two new experimental methods were used to evaluate a novel particulate TPA. The plugging performance of the TPA to the core end face and the propped fractures was measured through displacement experiments of cores, and the applicability of its basic performance to the temporary plugging fracturing was verified. Furthermore, the large-scale true triaxial simulation experiment of temporary plugging fracturing was carried out to confirm the influence mechanism of different factors on fracture propagation during temporary plugging. Finally, the influence rule of different types of combinations of TPA and placement patterns on the plugging was obtained based on laboratory evaluation of the conductivity. The results show that the novel TPA causes effective temporary plugging on the core end face and the propped fractures and has the strong plugging performance, and the TPA solubility in the carrying fluids decreases with the increase in the TPA concentration. The basic performance of the TPA meets the requirements of temporary plugging fracturing. If the proppants and 20% fibers are placed within the fracture in the mixed pattern, the fracture is initiated along the direction of the horizontal maximum principal stress. The preset fracture reduces the fracture initiation pressure. The fracture complexity is closely related to the placement pattern of TPA and proppants. If the preset fractures are filled by the uniform mixture or the plug of the 20/40 mesh or 20/80 mesh particulate TPA (4%), fibers (1%), and proppants, the fracture initiation pressure significantly increases, and the complex fractures are formed after fracturing. Effective plugging cannot be formed only by mixing the fibers with the proppants, and the uniform mixture of the proppants and 4% particulate TPA and the 6% particulate TPA at the front end of the fracture form a temporary plugging belt, achieving effective plugging. The fibers improve the conductivity under the low closure stress, and it has a certain effect of temporary plugging under the closure stress above 30 MPa. The research results provide the design consideration for creating the complex fracture by temporary plugging.

Influence of Inclination of Welding Torch on Weld Bead during Pulsed-GMAW Process.

This work is about the influence rule of inclination of welding torch on the formation and characteristics of weld bead during the pulsed-gas metal arc welding (GMAW) process based on the robotic operation. The inclination of welding torch was an important operation condition during the pulsed-GMAW process, because it can affect the formation and quality of weld bead, which was the output of the process. In this work, the different inclination modes and values were employed to conduct actual welding experiments, and some influence rules can be obtained according to examine the surface topography and cross section. Then, to obtain further rules, serious measurements for the geometry characteristic parameters were conducted and corresponding curve fitting equations between inclination angles and the bead width, penetration and bead height were obtained, and the largest error of these curve fitting equations was 0.117 mm, whose corresponding mean squared error (MSE) was 0.0103. Corresponding verification experiments validated the effectiveness of the curve fittings and showed the second order polynomials were proper, and the largest errors between measurements and curve fitting equations for inclination angle under backward mode were larger than those under forward mode, and were 0.10 mm and 0.15 mm, respectively, which corresponded to the penetration and were below 10%, therefore the equations can be used to predict the geometry of the weld bead. This work can benefit the process and operation optimization of the pulsed-GMAW process, both in the academic researches and actual industrial production.

Test and Analysis of Vibration Mode of Distribution Transformer Tank Structure

Along with the social and economic development and continuous increasing of electrical load, power distribution network has its scale continuously expanded, and more and more distribution transformers go deep into the urban residential areas, leading to increasingly serious vibration and noise problems. Relying on a typical 35 kV distribution transformer, a vibration mode test was done on the tank structure of the distribution transformer, and PolyLSCF fitting method was adopted to obtain the first 10-order modal shape in this paper. Meanwhile, finite element model was built for distribution transformer tank, and contrastive analysis were done in combination with the measured data to obtain the rules of influence on vibration mode of distribution transformer by tank wall thickness. The vibration characteristics acquired by measured mode of distribution transformer are consistent with those obtained by numerical simulation, and the central vibration amplitude of the tank is the maximum. Along with the increase of wall thickness, the low-order mode of the tank structure shows insignificant change, and high-order mode frequency reduces, thus providing measured data reference for optimizing the tank structure of distribution transformer.

Effect of Grading Type on the Performance of Warm-Mix Rubber-Asphalt Mixture

This paper designs three warm-mix rubber-asphalt mixtures with different grading types based on the Course Aggregate Void Filling method (CAVF) and standard method, and studies the rules of influence of the warm mixing effect and grading type of the warm-mix rubber-asphalt on the pavement performance of the mixtures through compaction temperature analysis, Marshall test, and rutting test. The results show that the compaction temperature of warm-mix rubber-asphalt mixture can be reduced by about 20 °C, and it has a significant warm mixing effect and excellent pavement performance.

The relationship between eccentric structure and super-lift device of all-terrain crane based on the overall stability

When the large all-terrain crane operated under ultra-high hoisting height, the stability of boom system became the key factor of the lifting capacity. The installation of eccentric structure and super-lift device could help to improve the stability of boom system. In order to achieve the best effect of growth, it was important to study the relationship between eccentric structure and super-lift device. The eigenvalue buckling analysis and geometric nonlinear buckling analysis were carried out by ANSYS for the combined boom system of 500 t all-terrain crane with tower jib when lifting load, dead weight, offset load, wind load and lifting rope force were considered. And then the influence rule of the combined relationship between the strut length, opening angle, amplitude variation angle of the eccentric structure and the strut length, opening angle, amplitude variation angle of the super-lift device on the overall stability of combined boom system was analyzed to obtain the optimum parameter combination of eccentric structure and super-lift device, which provides reference for engineering practice.

Enhanced magnetorheological effect and sedimentation stability of bimodal magnetorheological fluids doped with iron nanoparticles

The improvement of properties of magnetorheological fluids and mechanism study has long been a classic area within the field of magnetorheological materials. This article was undertaken to dope the iron nanoparticles synthesized by direct current electric arc discharge with the traditional carbonyl iron powders to prepare bimodal magnetorheological fluids with different doping ratios. Their rheological properties and sedimentation stability were evaluated to explore the influence rules and mechanisms. The results indicate that the effect of the addition of iron nanoparticles on rheological properties under magnetic field is a combination of two opposing factors such as the strengthening of the structure and the weakening of magnetization. The sedimentation stability of the bimodal magnetorheological fluids improved significantly with the increase in the proportion of iron nanoparticles, which is attributed to the help of both free state and adsorbed state iron nanoparticles in magnetorheological fluids. Furthermore, within a specific magnetic field strength range, the bimodal magnetorheological fluids with a small proportion of iron nanoparticles can achieve an improvement in both rheological property and sedimentation stability compared with carbonyl iron particles–based magnetorheological fluids.

Study on hole quality and surface quality of micro-drilling nickel-based single-crystal superalloy

Nickel-based single-crystal superalloy has no grain boundary. This makes the traditional cutting mechanism of shearing and slipping along grain boundary of polycrystalline material based on the theory of elastic–plastic deformation not suitable for drilling single-crystal parts. To achieve high-quality and low-damage micro-drilling of nickel-based single-crystal superalloy, the micro-drilling surface/subsurface quality of the (001) crystal plane of nickel-based single-crystal superalloy was studied in this paper. Firstly, the influence rules of the cutting speed (vs) and the feed rate (vw) on the micro-drilling hole size, surface morphology, surface roughness and subsurface damage depth were studied. Then, the micro-hardness on micro-drilling subsurface was analyzed. Finally, the subsurface recrystallization was explored. The results show that with the increase in vs, the hole diameter error and the surface roughness decrease, and the depth of subsurface plastic deformation layer decreases first and then increases; with the increase in vw, the error of hole diameter and the surface roughness increase, and the depth of the deformation layer decreases first and then increases. When vw > 0.33 μm/r, there are severe scratches on the surface of the hole wall, and the hole wall appears undulating stripes; white layer structure and severe plastic deformation layer appeared on the micro-drilling subsurface; the γ and γ’ phases' deformation is severe; the micro-hardness at the subsurface white layer is small, and the micro-hardness value at the plastic deformation zone is large; after the high-temperature treatment, γ phase dissolves on the subsurface of micro-drilling parts, and the cellular recrystallization and the complete recrystallization occur. The minimum thickness of recrystallization layer obtained is 1.43 μm at vs = 141 m/min and vw = 0.105 μm/r. This study provides a good guidance and reference for the machining of nickel-based single-crystal superalloy micro-hole parts.

Theoretical and numerical simulation study on jet formation and penetration of different liner structures driven by electromagnetic pressure

The use of a shaped liner driven by electromagnetic force is a new means of forming jets. To study the mechanism of jet formation driven by electromagnetic force, we considered the current skin effect and the characteristics of electromagnetic loading and established a coupling model of “Electric–Magnetic–Force” and the theoretical model of jet formation under electromagnetic force. The jet formation and penetration of conical and trumpet liners have been calculated. Then, a numerical simulation of liner collapse under electromagnetic force, jet generation, and the stretching motion were performed using an ANSYS multiphysics processor. The calculated jet velocity, jet shape, and depth of penetration were consistent with the experimental results, with a relative error of less than 10%. In addition, we calculated the jet formation of different curvature trumpet liners driven by the same loading condition and obtained the influence rule of the curvature of the liner on jet formation. Results show that the theoretical model and the ANSYS multiphysics numerical method can effectively calculate the jet formation of liners driven by electromagnetic force, and in a certain range, the greater the curvature of the liner is, the greater the jet velocity is.

Experimental Study on Tool Wear in Cutting Superalloy under High-Pressure Cooling

Superalloy is widely used in the aerospace industry and is a typical difficult-to-cut material. PCBN tool has good cutting efficiency in processing superalloy, but it has a larger cutting force, higher cutting temperature and severe tool wear in the cutting process. High-pressure cooling has great advantages in processing high strength steels such as superalloy, which can effectively reduce cutting temperature and improve tool-chip breaking performance, thereby reducing tool wear. Therefore, it is of theoretical significance and practical value to study tool wear mechanism of PCBN tool cutting superalloy under high-pressure cooling. Firstly, the wear form of the flank is analyzed to provide theoretical support for tool wear research; Secondly, the experimental study of tool wear under high-pressure cooling is carried out. The tool wear under different cutting time, cutting speed and cooling pressure is analyzed respectively, and the influence rule of different cutting conditions on tool wear is obtained; Finally, a tool wear prediction model under high-pressure cooling is established to provide theoretical basis and technical methods for efficient processing of superalloy and optimization of cutting parameters under high-pressure cooling.

Thermal behavior analysis of hollow bricks filled with phase-change material (PCM)

Light-weight materials are comprehensively used to reduce the building weight in high-rise or super high-rise buildings, but they will reduce building thermal inertia remarkably, which can increase the air-conditioning load fluctuation and reduce indoor thermal comfortable. According to this condition, phase-change material (PCM) is filled to hollow bricks to improve thermal behavior by latent thermal storage. A numerical model with the heat transfer process of melting-solidifying was built, and a full-scale experiment was done to verify this model. Due to the filled PCM, the thermal performance of hollow bricks was improved obviously from experimental and numerical results. Under suitable phase-change temperature, the filled PCM can reduce the attenuation rate from 13.07% to 0.92%–1.93% and increase the delay time from 3.83 h to 8.83h–9.83 h. Meanwhile, the filled PCM can reduce the peak heat flux from 45.26 W/m2 to 19.19 W/m2-21.4 W/m2, but cannot reduce the average value. In addition, inner cavities were the better choice for PCM and there was an extra phase-change extent of close to 90% in favor of the different outdoor thermal environment. Finally, influence rules of latent heat and thermal conductivity coefficient of PCM were analyzed on temperature and heat flux in inner surfaces.

Establishment of a Two-Stage Turbocharging System Model and Analysis on Influence Rules of Key Parameters

This paper took a two-stage turbocharged heavy-duty six-cylinder diesel engine as the research object and established a two-stage turbocharging system matching model. The influence rules between the two-stage turbocharging key parameters were analyzed, while summarizing an optimization method of key parameters of a two-stage turbocharger. The constraint equations for the optimal distribution principle of the two-stage turbocharger’s pressure ratio and expansion ratio were proposed. The results show that when the pressure ratio constraint equation and expansion ratio constraint equation are satisfied, the diesel engine can achieve the target pressure ratio, while the total energy consumption of the turbocharger is the lowest.